Exhaust discharge for outboard motors



June 24, 1952 H. P. HENRY 2,601,396

EXHAUST DISCHARGE FOR OUTBOARD MOTORS Filed July 20, 1948 2 SHEETS-SHEET 2 INVENTOR. gomqen/ fi'A z/ver Y fizz saga cf a/uw Patented June 24, 1952 OFFICE EXHAUST DISCHARGE FOR OUTBOARD MOTORS Howarth P. Henry, Yellow Springs, Ohio Application July 20, 1948, Serial No. 39,662

This invention relates to improvements in exhaust discharge for an outboard motor.

An object is to provide an outboard motor which is not only capable of fulfilling all of the normal functions of a conventional outboard motor, but is also adapted to so function as to drive a boat at a relatively slow speed suitable for trolling.

Another object is to provide the conventional outboard motor with improved inexpensive means whereby the motor may be selectively operated to propel a boat to which the motor is attached either at conventional speeds normal to such motor or to propel the boat at a relatively slower speed.

More particularly I provide simple means which may be associated with the exhaust outlet of a conventional outboard motor whereby the motor is so modified that it may be operated either to drive a boat at speeds normal to the conventional functioning of the motor or to drive the boat at a substantially reduced rate of speed which would be suitable for trolling.

This improvement may be easily adapted to conventional outboard motors such as are now on the market. It is of simple construction and will not interfere with the normal functioning of the motor. It will not add materially to the cost of a motor equipped therewith. It does not involve regulating the running speed of the motor but pertains to selective emission of the exhaust gases of the motor with respect to the propeller wheel with which the motor is equipped.

More specifically an object is to provide an outboard motor having a propeller and having an exhaust discharge outlet directly rearwardly of the propeller with a second exhaust discharge outlet directly forwardly of the propeller and to provide control means whereby the exhaust from the motor may be discharged through either outlet. The discharge outlet to the rear of the propeller is the normal outlet that is conventional in outboard motors, and by providing a discharge outlet ahead of the propeller, the introduction of gases into the water at this point causes cavitation and reduces the propulsive thrust to such an extent that the speed of a vessel propelled thereby is sharply reduced.

Control of the discharge of exhaust gas selectively through the two discharge outlets, one ahead of the propeller and the other rearwardly thereof, may be accomplished by manual means or it may be accomplished by automatic means. The preferred embodiment illustrates manual control. A modification is shown where- Claims. (Cl. 115-17) in the control mechanism is responsive to the position of the control lever which regulates the speed of the motor. Another modification illustrates a control mechanism which is responsive to a control member which is actuated by movement of the boat carrying the outboard through the water.

Other objects, advantages and meritorious features will more fully appear from. the following specification, claims and accompanying drawing, wherein:

Fig. 1 is a side elevation of an outboard motor partly broken away embodying my invention and showing the same attached to the stern of a boat.

Fig. 2 is a vertical sectional view through the lower end of a motor shaft showing the propeller and the exhaust.

Fig. 3 is a perspective of a fraction of the motor shaft casing broken away to show the exhaust openings and the means for rotating the valve control 2.

Fig. 4 is a perspective of a modified embodiment of my invention.

Fig. 5 is a fragmentary elevation of the construction shown in Fig. 4.

Fig. 6 is an elevation partly in section of the propeller and of the shaft showing a second modification.

Fig. 7 is a horizontal sectional view taken on the line 1-'l of Fig. 6.

Fig. 8 is a perspective of the outlet and of the exhaust showing a part of the control mechanism embodied in Figs. 6 and 7.

My particular invention is adapted to be embodied in any conventional outboard mot-or and relates to the exhaust outlets and their association 'withthe propeller. In Fig. l of the drawing a conventional outboard motor is indicated as ID. It is shown as attached by a clamp [2 to the stern I4 of a row boat orthe like. The motor may be of any suitable internal combustion type provided with the usual controls which specifically form no part of the instant invention.

The motor is provided with a driven shaft 16 shown specifically in Figs. 2 and 3. A hearing I8 is shown in Fig. 2 for the lower end of the shaft. The upper end of the shaft is provided with suitable bearings not shown. Upon the lower. end of the shaft is mounted a pinion 20. This pinion 20 is engaged with a pinion 212 carried by a stubshaft 24. A propeller 26 is mounted upon this stub shaft to rotate therewith. This is standard conventional propeller mechanism for conventional outboard motors.

Surrounding the shaft IE but spaced therefrom is the casing or sleeve 28. This casing extends from the motor casing at the top to an assembly 29 at the bottom which includes an exhaust outlet part which is rigid with the casing and arches to the rear over the propeller as shown in Figs. 2 and 3 and has an exhaust opening 32 which discharges directly aft of the propeller 26 as shown in Fig 2, this location being typically illustrative of a non-cavitating exhaust opening position. There is mounted within the casing 28 for rotatable adjustment about its longitudinal axis, an upright tube '34. This tube serves as the exhaust conduit from the motor. The tube is supported spaced within the casing by suitable spacing rings. The casing which includes the exhaust outlet 30 provides one such support 3| for the tube. The second ring'is' shown as located intermediate the top and bottom of the casing 28 and is indicated by the numeral -36.

This tube is provided withaseries of discharge outlets for'exhaustgas. One such outlet is-indicatedat 38. It is adapted toregister withthe normal discharge outlet 32 shown in .Fig. 2. Another discharge outlet is indicated as 40. .It is positioned below the outlet 38 and is slightly offset therefrom circumferentially of the tube 34. "This outlet 40 is adapted to register with .a discharge outlet 42 through'the casing r28 which outlet 42 is located below the outlet 32 and 01T- set 'circumferentially to correspond with the offsetting of the ports 38 and 4|] through the tube 3'4.

When the port 38 is registered with theexhaustoutlet 32 the port 40 is not registered 'with the :exhaust outlet '42 and vice. versa. The tube 34 is provided with still .another outlet port disposed above the water :line and indicated by numeral and which is adapted to register in one position of rotation of the tube with an :exhaust port 46 through the casing '2i8.and through the sleeve bearing 36.

The tube 34 is rotatable :bytme'ansof .a handle 48 which is secured thereto and which handle has a shank whereby the tube .may'be rotated about its longitudinal axis. In one position of rotation the port 44 registers with the outlet 46. This might be termed the starting position. In anotherposition .of rotation the port 38.reg'isters with the exhaust outlet 23!. This is the normal cruising position. :In another rotatable "position the'port '40 registers 'with the discharge outlet 42. This discharge is zahead of the propeller .126 in a position such that the gases de- .livered :therethrough will tend to cause cavitation. The resulting cavitation will so :reduce the ipropulsive force of the propeller that the speed :of the boat will be reduced to .a speed suitable for trolling.

In order to ,positivelyhold the valve tube :34 at'adjusted positions as described, the .slot 50 isshown as provided with notches 52 and the .shank 1011 the handle 48 isishown :faspivoted as 'at 53 so that its-outer end may swing downinto 'a 'notch as illustrated tohold the tube positively against dislocation. In Fig. .3 the difierent positions to which the valve tube may "be rotated .are indicated by letters which :may be stamped .upon the casing opposite the notches 750. For example, the letter S would indicate starting; theletter "C cruising; and the letterTitrolling; as to :positions to which the tube had :been moved.

Figs. 4 through :8 'show automatic rather than valve tube 34 is provided with a pin 64 which extends through a slot 66 in the casing 28. An arm 68 is pivoted at 10 to a base member 12 which forms a part of the motor assembly and swings therewith when actuated by the handle 11. The lower end of this arm is bent inwardly as at 14 and forked to engage over the pin 64 as shown in Figs. 4 and 5. The opposite end of the arm is forked as at 16 to engage over a pin '18 which pin is fixed to the plate 62. vIt is apparent that when .the .plate 621s rotated by the control member 60, the arm 68 will :be swung upon its pivot 10 and will actuate the tube 34.

It is apparent that through this connection between the valve tube 34 and the magneto control lever actuated plate 62, the valve tube will be rotated as the magneto throttle lever is swung. The port :arrangementof the valve tube is, as has already been discussed in connection withFigs. 1, 2 and 3, so arranged that'therejs a low speed position at which the tube is 1'0- tated to discharge throughthe opening! at the lowerend of the tube and the opening 42 in the casing forwardly of the propeller 126 so as to reduce its effectiveness and facilitate trolling. At high speeds the port 38 of the tube communicates with the discharge outlet '32 which is the normal one. This construction does not show any third port corresponding'to the port 44 of Fig. 2 through obviously such an outlet might be provided, if desired.

In Figs. 6, '7 and 8 another type of automatic control is provided. In these figures a plate is pivotally supported upon the pins -82, secured to theexhaust'outlet pipe *35. This plate 83 may be journalled upon both sides to the :pivots 82 as shown in Fig. '7. A bell crank lever 84 extends upwardly irom'the plate 86 and a tension -spring 85 acts thereupon to hold'the plate 80 at the position shown in Figs. '6 and 8. "In this position it is extended rearwardly at an angle.

' There is linkage which connects this 'bellcrank lever'withthe valve'tube. This tube 34 is shown as having'a pin88 projecting rearwardly therefrom through a slot 90 formed-on the casing 2-8. A link'92 extends from this 'pin to the bellcrank lever 84. "The valve tube is provided with the openings 36 and 4D 'hereinabove-described which openings are adapted to register with discharge outlets 3-2 and 42 also hereinabove described.

At the lowspeed position the spring 86 holds the "plate '80 to the solid line position shown "in Fig. Sand Fig. 8. Insuch position of the plate, the valve tube is held :to discharge through the port '40 and outlet '42 ahead of the propeller26. When the engine is speeded up, the plate iii) is swung to the rear and into asubstantiallyhorh vz'ontal position by virtue of the action of 'the wheel and the travel ofthe .boat through the water. In this horizontal position, thelink 32 :is moved to rotate the valve tube 34 so that the exhaust is through the port .38 and outlet .32

and aft of the -propeller'26.

What I claim is:

1. The combination with an outboard motor including an exhaust manifold, a propeller shaft, a propeller drivably connected to said shaft, and a propeller shaft housing, of a tubular sleeve in said housing surrounding said shaft and connected to said manifold to conduct exhaust gases away from said motor, a first underwater exhaust port in said housing positioned forwardly of said propeller to direct substantially all of the exhaust gases emitted therefrom against said propeller, a second underwater exhaust port in said housing positioned to expel exhaust gases rearwardly of said propeller without impinging thereagainst, said sleeve having two openings therein each of which is registered with a different one of said exhaust ports upon turning said sleeve in said housing between two difierent positions, and means for turning said sleeve between said two positions.

2. The combination with an outboard motor including an exhaust manifold, a primary engine control member, a propeller shaft, a propeller drivably connected to said shaft, and a propeller shaft housing, of a sleeve in said housing surrounding said shaft, said sleeve turnable relative to said housing, said sleeve being connected to said exhaust manifold to receive exhaust gases therefrom, means interconnecting said engine control member and said sleeve to rotate said sleeve upon movement of said member between two positions, a first underwater exhaust port in said housing positioned forwardly of said propeller to direct substantially all of the exhaust gases emitted therefrom against said propeller, a second underwater exhaust port in said housing positioned to expel exhaust gases rearwardly of said propeller without impinging thereagainst, said sleeve having two openings therein each of which is registered with a different one of said exhaust ports upon movement of said engine control member between said two positions.

3. The combination with an outboard motor including an exhaust manifold, a propeller shaft, a propeller drivably connected to said shaft, and a propeller shaft housing, of a tubular sleeve in said housing surrounding said shaft and connected to said manifold to conduct exhaust gases away from said motor, a first underwater exhaust port in said housing positioned forwardly of said propeller to direct substantially all of the exhaust gases emitted therefrom against said propeller, a second underwater exhaust port in said housing positioned to expel exhaust gases rearwardly of said propeller without impinging thereagainst, said sleeve having two openings therein each of which may be brought into registration with a different one of said exhaust ports upon turning said sleeve in said housing, a plate, means hingedly securing said plate to said housing for movement between a first position wherein said plate intercepts the wash of said propeller and a second position wherein said plate is swung clear of the wash of said propeller, spring means urging said plate into said first position, and linkage interconnecting said plate and said sleeve (1) to connect one of said sleeve openings with said first exhaust port when said plate is in said first position and (2) to connect the other of said sleeve openings with said second exhaust port when said plate is in said second position, whereby at low engine speeds exhaust gases are discharged directly against said propeller to promote cavitation and reduce the effective thrust of said propeller.

4. In an outboard motor including an exhaust manifold, a propeller shaft and a propeller drivably connected to said shaft, the combination comprising: an exhaust line connected to said exhaust manifold and including an exhaust pipe surrounding a portion 'of said propeller shaft. said exhaust pipe having two outlets therein positioned to open below the surface of the water when said outboard motor is in use, one of said outlets being positioned directly in front of said propeller to discharge exhaust gases directly against said propeller, the other of said outlets being positioned directly behind said propeller to discharge exhaust gases away from said propeller so as not to impinge thereagainst, and means for selectively distributing the exhaust gases between said two outlets.

5. In a marine internal combustion engine including a, propeller, means for utilizing the exhaust gases of said engine to control the effective thrust of said propeller, said thrust control means comprising: an exhaust line from said engine having a first exhaust outlet positioned directly in front of said propeller to direct exhaust gases below the water and against said propeller, a second exhaust outlet positioned directly behind said propeller to direct exhaust gases below the water and away from said propeller, valve means for closing said first exhaust outlet to discharge said exhaust gases through said second exhaust outlet, and means for actuating said valve means.

' HOWAR'I'H P. HENRY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,073,920 Miller Sept. 23, 1913 1,103,188 Filippi July 14, 1914 1,824,737 Johnson et al Sept. 22:, 1931 2,064,463 Crosley Dec. 15, 1936 2,082,059 Irgens June 1., 1937 2,139,831 Langstaff Dec. 13, 1938 FOREIGN PATENTS Number Country Date 19.047 Great Britain Sept. 10, 1908 460,165 Germany May 24, 1928 

